Botín took over as UK chief in December 2010. She becomes one of Britain's best paid female executives after taking home £2.2m in cash, with the remainder, a mix of cash and shares, to vest between the end of 2012 and 2015. Botín's basic salary in 2011 was £1.7m. It compares with a package worth £2.17m for Cynthia Carroll, chief executive of mining group Anglo American, while Royal Bank of Scotland's head of US operations, Ellen Alemany, may receive as much as £4.8m this year.

A spokesman for Santander UK said the bank "was sensitive to public opinion over the issue of remuneration for bankers, but our pay policy reflects the success of the business".

He added: "Santander UK has delivered a solid performance in difficult conditions without resorting to government assistance, generating consistent profits and cash for the Santander group, which in turn has paid €24bn (£20bn) to shareholders over the last five years, and of which 1.6m reside in the UK."

Santander also pointed out its British operation last year increased lending to small and medium sized businesses (SMEs) by 25%, exceeding government targets by lending £8.7bn to UK companies, with around half that figure made up of loans to SMEs.

But Santander UK was fined £1.5m by the City regulator for failing to make clear to thousands of investors that two of its investment plans were not fully covered by the Financial Services Compensation Scheme, despite the fact that both were sold as "guaranteed" bonds.

The Financial Services Authority said that despite the fact that Santander received many queries from its customers, it did not clarify the position until early 2010.

Ana Botín has worked at Santander since 1988. She was parachuted in from Spain to take over the UK arm when António Horta-Osório suddenly quit to run Lloyds Banking Group.

In Britain, where the Spanish bank bought Abbey National, Alliance & Leicester and part of Bradford & Bingley, Botín warned in February that "2012 is likely to be a tough year for the UK banking industry".

She added: "Economic prospects have deteriorated markedly even in recent months, whilst increased regulatory burdens and funding costs will impact the results further."

A flotation of the UK business, already severely delayed, now appears to be more than a year away as it grapples with an economy that is growing more slowly than it had expected.